Tow tractor



FIG. 1 is a front, top and left side perspective view of a tow tractor showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a left side view thereof.

The bottom plan view is omitted since it is unornamented and forms no part of the claimed design. The broken lines illustrate portions of the tow tractor and form no part of the claimed design. 

CLAIM The ornamental design for a tow tractor, as shown and described. 